Field of the Invention
The present invention relates to a process and an apparatus for separating particulate matter from a contaminated gaseous medium containing the particulate matter.
Processes for separating particulate matter from a contaminated gaseous medium are well known. In one such process, the contaminated gaseous medium containing the particulate matter is passed through a swirl-inducing zone. The resulting swirling-contaminated gaseous medium is thereafter introduced into a cyclonic separation zone adjacent to the inner surface of the swirl-inducing zone to (1) separate at least a portion of the particulate matter from the swirling-contaminated gaseous medium and (2) form a gaseous product which is at least partially depleted of particulate matter. The gaseous product is thereafter removed from the separation zone through an exhaust flow zone disposed radially inward from the swirl-inducing zone.
In U.S. Pat. No. 4,212,653, an improved process for increasing separation efficiency is disclosed. In this process, a substantially contaminant-free gaseous medium is passed through an additional swirl-inducing zone to form a coswirling mass thereof, and the coswirling gaseous medium is introduced into the separation zone through an introduction zone disposed radially inward from the swirling-contaminated gaseous medium and radially outward from the exhaust flow zone. The purpose of the introduction of the coswirling substantially contaminant-free gaseous medium is to shield the contaminated medium from the exhaust flow zone and the eddy currents developed upon introduction of the contaminant-laden medium.
However, the two processes described above have not been entirely satisfactory from the standpoint of separation efficiency. It has now been found that the substantial increases in separation efficiency of the above-described separation processes are obtained by the practice of this invention, which provides an improvement to the processes.